This invention relates to a releasable plug-in connector for receiving a tubular plug-in part with a peripheral retaining rib. The plug-in part may be the end of a relatively rigid metal tube which is used, for example, for fuel lines. It may also, however, in the same way as the connector, be made of a rigid plastic or other common injection-molded material which can be connected in a known manner to a hose line or pipeline.
U.S. Pat. No. 4,844,512 discloses a plug-in connector of this type, in which, at the entrance end of the receiving housing, are located integrally formed retaining edges, which are provided with oblique introduction surfaces and are in the form of an arc of a circle, diametrically opposite one another, on an inner wall of the housing. The entrance end is designed with two mutually shaped, diametrically opposed openings, thus forming a peripheral ring at the entrance end connected to the housing by webs. The retaining edges are located on the inner wall of this ring and are aligned with the webs.
The housing is made of a hard, resilient plastic material, the peripheral ring deforming as the plug-in part is pushed in, so that the retaining edges will yield radially outwards and spring back into a closed position again after a complimentary peripheral retaining rib on the plug-in part has passed them. This connection can be released by pressing the ring together between the retaining edges, so that the retaining edges will move outwards into a release or open position, thus releasing the retaining rib of the plug-in part, allowing it to be pulled out of the receiving housing.
A disadvantage of this plug-in connector is that the housing has to be produced from a material elastic enough to allow the peripheral ring to be correspondingly deformed. Consequently, the plug-in connector is suitable, at best, for low-pressure lines. It is not suitable for high-pressure lines, owing to the retaining forces required for the latter. There is also the danger, in the case of the elastic ring lying exposed in the front part of the receiving housing, that it may be unintentionally pressed together during assembly work, thus moving the retaining edges so far outwards that the plug-in part can spring out of its own accord.
An object of the present invention, therefore, is to configure the connecting parts such that, along with a stable receiving housing, a solid and permanent plug-in connection can be achieved which, in particular, is fully secure even in the high-pressure range. A further object is to ensure, by suitable structural measures, that an undesired opening of the connection--or release of the plug-in part--is avoided.